Improved resistive switching properties by nitrogen doping in tungsten oxide thin films

Abstract

In this study, nitrogen-doped WOx thin films are investigated for the improvement of resistive switching (RS) properties. Compared to WOx thin films, nitrogen-doped WOx thin films exhibit a higher on/off current ratio (a separation of similar to 2 orders of magnitude), better endurance (> 100 cycles), narrower current dispersion, and longer retention characteristics (> 10(4) s). Electrical measurements, X-ray diffraction, and X-ray photoelectron spectroscopy demonstrate that nitrogen in WOx:N thin films forms WN nanoclusters and W-x (O, N) phases, which are beneficial to improve the RS properties in WOx thin films; WN nanoclusters can locally enhance the electric field to form stable conductive filament while W-x (O, N) phases can suppress random migrations of oxygen ions (O2-), leading to stable RS characteristics. Our findings suggest that nitrogen doping method can lead further optimization of the RS characteristics in WOx thin films. (C) 2015 Elsevier B.V. All rights reserved.